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Mitsubishi Mini Splits. "Best way" to run them and maintain?

joea99
joea99 Member Posts: 42
edited March 19 in Gas Heating
Was following the "convert to gas now" thread and Mini Splits came up.

Rather than hijack that tread, I'd like to get into the best way to run them and also how to best maintain them, that is, clean the interior units.

I had 4 units installed, a 12k unit in a large open area, and 3 8k units in bedrooms and smaller room. Overkill maybe, but I did not buy the idea that 1 unit could "do the whole house", not seeing how enough heat or cooling could get everywhere to maintain a reasonable temperature distribution. And, I'd have "some" service if one unit went down.

The outfit that installed them said to "just let them run" which I understood to mean not to bother with the timers and just leave it at desired temperature. They did not mention inside unit cleaning at all, but did offer "annual maintenance". At $200 per unit.

I was astounded to see, after two seasons that the interior units were filthy, despite having maintained the two pre filters quite regularly. Ended up reading up on the issue and cleaned them myself, but it IS a PITA. Are there methods other than essentially partially disassembling the units?

Comments

  • wmgeorge
    wmgeorge Member Posts: 222
    edited March 19
    I was surprised at the amount of dirt inside my blower wheel fins and coil after 2 1/2 years... Since my shop is close by I ran an air hose and made up an copper tube adapter to blow out those pesky blower fins, with a shop vac running.

    Mistake. I then needed to clean the entire room but the fins were clean and moved a Lot more air.

    I have checked and cleaned the POS filters like you but no Help. Ended up with some filter coat spray and will see if that helps.

    Amazon sells Bib kits and complete cleaning kits and I will order for next time. For my Next time I ordered a air operated with water tank/ soap tank that can fit through those lower vanes and spray clean those fins. I will order the bib kit that encloses the entire lower section with a drain tube to a 5 gallon bucket.
    Old retired Commercial HVAC/R guy in Iowa. Master electrician.
  • joea99
    joea99 Member Posts: 42
    I ordered the bib/shroud after doing the first one without it. Used the "no rise" cleaners from Calgon but rinsed with clean water anyway. That "citrusy" smell that talk about . . . still smells like "cleaner" to me.

    Did remove the blower wheel on each and even so, found it really hard to get them clean. Maybe next time I'll just try compressed air, outdoors or a pressure washer. Don't see how a thorough cleaning can be done without removing the enclosure and it makes me nervous having to move the coil unit at all.

    Disappointing to have this maintenance "flaw" in an otherwise great unit.
  • wmgeorge
    wmgeorge Member Posts: 222
    edited March 19
    The sprayer I got from Amazon was $48 and uses compressed air to power the water spray.

    https://www.amazon.com/dp/B01E0FXD18?psc=1&ref=ppx_yo2_dt_b_product_details

    I could get the one I made through those vanes at the bottom. They are just stepper motors and you can gently open them wide open with the power off to the unit. They will Reset when power is applied. My compressed air method got them 95% clean. I would Never remove that motor or blade unless it needed replaced!
    Old retired Commercial HVAC/R guy in Iowa. Master electrician.
  • joea99
    joea99 Member Posts: 42
    wmgeorge said:

    The sprayer I got from Amazon was $48 and uses compressed air to power the water spray.

    https://www.amazon.com/dp/B01E0FXD18?psc=1&ref=ppx_yo2_dt_b_product_details

    I could get the one I made through those vanes at the bottom. They are just stepper motors and you can gently open them wide open with the power off to the unit. They will Reset when power is applied. My compressed air method got them 95% clean. I would Never remove that motor or blade unless it needed replaced!

    I was worried about removing the squirrel cage blower, but here is only one screw holding it it, once the stuff in the way is moved. Hard to find the screw head until you've done it a couple of times. Then it almost "falls to hand".

    There is a lot of gunk in back of it in the air flow path as well that I don't think will come out without being wiped down. It would certainly be easier to not have to remove it.

    What do you do about the evap coil?
  • GW
    GW Member Posts: 4,542
    Minisplits-- no way to know how the environment will treat each and every mini split installation. I have seen some, a few years old, look brand new. I have seen one, a 6 months old, look like it was 8 years old. Carpeting, laundry, kids, pets, general cleanliness, lots of plants, all play a role. Run time is obvious factor (AC only, or heating too?)

    Taking them apart: kinda need to like to tinker. It's not for everyone. The first time I took one apart, I thought for sure something was going to break!

    I prefer to pull the wheel, if it's nasty and caked, you would need some serious washing to clean things up. But both methods are totally good (Bib kit and wash in place, or, disassembly).

    Yes, some of the hvac guys don't spell out the maintenance very well, if at all.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
    wmgeorge
  • ayetchvacker
    ayetchvacker Member Posts: 55
    Partially disassembling them is necessary with wall mounted ductless units. It’s a consequence of the design. Frequency will depend on the environment and how much they’re used. Either get proficient at dismantling and cleaning or find a good company that knows how to do it. Either way DO NOT SKIP IT! Nasty nasty things will happen if you ignore them. And yes the contractors who sell them SHOULD tell the buyers that thorough cleaning is required and it needs to be professionally done IMHO.
    Fixer of things 
    Lead Service Technician
    HVAC/R
    ‘09Moto Guzzi V7
    ‘72CB350
    ’83Porsche944
  • joea99
    joea99 Member Posts: 42
    What sort of "nasty nasty things" will happen, besides the mold and filth I found in these. I certainly would not want to let it get that bad again, but beyond any smell and health issues, what sort of problems?
  • wmgeorge
    wmgeorge Member Posts: 222
    edited March 20
    Joe the inside coil inlet faces you when you remove the filter. Shop vac it out and angle spray will clean it, After running service for over 30 years I learned how to do things fast and easy. I have no intention of removing the blower wheel to clean and I have already got it done for this year!! Airflow is fantastic same as new.

    But I will order the Bib Kit less the sprayer for next time. My wife did like my cleaning job on the room however :p
    Old retired Commercial HVAC/R guy in Iowa. Master electrician.
  • clammy
    clammy Member Posts: 2,740
    Here’s a quick guide to maintance ,clean filter at a mim monthly . Yearly maintance should include removing the cover ,cleaning it and wiping down w Lysol or spray nine to kill any bacteria , remove blower wheel, usually spray nine and hose off w water re line the blower wheel bearing or replace there kinda cheap and using silicone based oil on bearing if just re oiling , spray coil w a no rinse bacterial indoor coil cleaner yet still rinse w water , ensure condensate line is clear and draining properly , re assembly and add a anti bacterial pad to the condensate tray . I have notice less build up of crap in the condensate line since I started using them . Clean the base and coil on the out door unit even I feel it looks clean it usually is not and it pretty easy to do so as Nike says just do it dirty outdoor lead to running higher head pressure which in the long run lower eff and lowers life span . At most it takes 10 to 15 minutes to spray foam and rinse well ensuring a clean coil , it may look clean but air pollutants and pollen build up and decrease your efficiency . I think when selling mini splits the cost of maintance should be talked about very seriously ,I see in some cases that when cost and life span come into play that mini splits may be a short term answers to a home which could have had central ac retro install done w a longer life span less costly maintance over time . Also at 200 buck per inside unit I would not be running to clean your indoor unit any time soon . I always fully explain the costs and if I see the home owners are not very good house keepers then I might even pass on the job nothing worse then clean mini splits 2 times a season and hearing complaints due to no house keeping and dusty environments and pet hair and dander every where . Not ever home or ever home owner needs a mini split ,they all have there place .
    Peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
    reggiwmgeorge
  • joea99
    joea99 Member Posts: 42
    "Also at 200 buck per inside unit I would not be running to clean your indoor unit any time soon . "

    I guess you are saying you would not do that job for $200?